1. Field of the Invention
The present invention relates to an antenna, and in particular of to the dipole antenna employed in a laptop computer, a portable electrical device or other electrical devices.
2. Description of the Prior Art or Related Art
With the development of wireless communication, transmitting and receiving information without infection by the environment is very preferable to user. However, the quality of the wireless communication largely depend on the performance and pattern of the antenna in which the signal is transmitted. So, the quality performance of the antenna is very important to the wireless communication between electronic devices, such as Notebook computer and wireless router.
The conventional dipole antenna or helix antenna usually needs a great deal of inner space of electrical device so as to be properly installed therein. It becomes an obstacle of the trend of miniaturization development of the wireless communication device. As a result, an antenna printed on a substrate, such as PCB, which needs less and relatively small space is used in portable electrical device.
The PCB antenna concentrates wireless transport components on one PCB. So, the PCB antenna not only occupies small space but also can make cost down of the manufacture.
For example, TW Patent No. 253069 discloses a printed dipole antenna. Referring to FIG. 1, the printed dipole antenna comprises a radiating element 16, a grounding element 18, an insulative patch 10 and a conductor line (not show). The radiating element 16 is located on the left side of the insulative patch and the grounding element 18 is located on the right side of the insulative patch. The radiating element 16 has a first feeding point 5, while the grounding element 18 has a second feeding point 7. The inner conductor of the conductor line is soldered to the first feeding point 5 and the braiding layer of the conductor line is soldered to the second feeding point 7.
Though the dipole antenna disclosed in TW 253069 occupies small space, the radiating element 16 and the grounding element 18 are separated from each other, when the dipole antenna encounters or operated under an intense electromagnetic field, the background noises transmitted from the intense electromagnetic field would arrive at system through the radiating element 16. As a result, the antenna system will fail to distinguish which is working signal and which is from the background noises and cause the system fail to work functionally.
Hence, in this art, a printed antenna to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiment.